20 Vegetable Physiology. 



phenomena which some of these exhibit, such as the closing 

 of the leaves of the Sensitive Plant on being touched, must be 

 familiar to every one. The little Dioncea Muscipula, or as it 

 is commonly called, Venus' Fly-trap, which inhabits the 

 swamps of many parts of this country, is another singular 

 instance. The leaf is formed, or rather has an appendage, of 

 two lobes, on the edges of which are long, slender and sharp 

 spines, and in the centre a viscous fluid, which is attractive to 

 insects. Whenever one of these alights on the leaf, for the 

 purpose of tasting this fluid, the two lobes suddenly contract, 

 close themselves together, and with their spines pierce through 

 and confine the un^rtunate victim. The Sun-dew, (Drosera 

 rotundifolia,) also a common inhabitant of the northern states, 

 has its leaves covered with brown upright filaments, on the 

 top of which is a globule of clear fluid, and which on being 

 touched, instantly fall down. The common Barberry, (Berbe- 

 ris Canadensis,) presents another instance, which may readily 

 be observed. On touching with a pin the lower part of the 

 stamens, they instantly throw themselves forward against the 

 pistil. These and other similar phenomena are caused, how- 

 ever, by no voluntary power like that exerted in the movement 

 of animal muscles, but are explained on entirely mechanical 

 principles. But there are many respects in which animals and 

 plants agree. They are both produced from a germ or egg, 

 they increase by the assimilation of foreign matter, they grad- 

 ually reach their full developement, propagate their species, 

 decay, and at last lose their vitality, become subject to the 

 decomposing influence of the atmosphere, are dispersed, and 

 their elements enter into new combinations. Plants respire 

 air, and have a continual motion of their fluids, which, like those 

 of animals, are partly converted into the solid matter which 

 enters into their composition, and partly escape through the 

 pores of their outward surfaces. Yet these analogies are far 

 from being perfect, and the organs of plants can bear but a 

 limited comparison with those of animals. Of these affinities 

 we shall take more particular notice when we enter upon the 

 explanation of the structure and functions of the different parts 

 of vegetables, as a preliminary to which these concise remarks 

 are offered. 



